Stadia-rod.



Patentsd July 9, I90I.

n.1., SANDERSU.

sTAmA non.. (Applcatipn ld Max'. 25, 1901.)

(No Model.)

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THE Noam: PETERS co., PHormuTNa, wnsmnoron, n r:4

UNITED STATES YPATENT OFFICE.

GEORGE L. SANDERSON, OF ANTESFORT, PENNSYLVANIA. l

STADIA-ROD.

,SPEQEFICATION forming* part f Letters Patent N0. 678,041, dated July 9, 1901. Applicationled March 25,1901. Serial No. 52,683. (No model.)

T0 @ZZ whom it may concern:

Be it known that I, GEORGEL. SANDERSON,

of Antesfort, Pennsylvania, have invented a tion with a sight having a compound cross-y rod in proper position.

new and useful Improvement in stadia-Rods,-

of which the following is a specification.

My invention relates to a stadia-rod, such as used in surveying and for the making of stadia measurements.

The object of the invention is to improve the construction and render more easythe manipulation and reading of the rod in use.

The invention consists in a stadiaerod constructed as hereinafter described, and more particularly pointed out in the claims.

A stadia-rod is commonly used in connecwire ring or diaphragm provided with three horizontal wires. The rod itself is commonly marked off with spaces, which should be equal to that which the instrument intercepts at one hundred feet.

The rod is also commonly provided with two movable targets, such as are used on leveling-rods and with an attached plumb or level. point marked uponthe rod at the ordinary height of the horizontal axis of the sighting In using the sight the middle height of instrument marked on the rod,

and the targets are then moved successively' thereon untilthey coincide with the outer wires, the rod of course being kept Vertical. It' the telescope has been level during this' operation, the distance given by the rod plus theV instrument-constant can be recorded. If the line of sight has been elevated or depressed, then the distance given by the rod with certain corrections is taken. Stadia measurements thus made are as reliable as chain measurements upon fairly-level ground and are much more accurate than chain measurements on broken country.

It has been found in practice almostimpossible for the most expert rodman successively to move the targets on the rod, as above described, and at the same time to keep the It requires many movements to bring the two targets into correct line and much waste of time. Furthermore, the engineer at the telescope finds difficulty at a distance of tive hundred or a thousand feet in directing the successive adapted to slide on the rod B.

There is also a' vwrong, so that the reading of the rod is rendered incorrect. For this reason stadia-rods have been made without targets and the engineer left to read the spaces on the rod which the instrument intercepts at a distance through the transit-telescope, which is very difficult to do correctly.

My invention overcomes the difficulties of the stadia-rod before mentioned. Referring to the accompanying drawings, Figure lis a front elevation. Fig. 2 is a side elevation. Fig. 3 is a vertical section on the line 3 3, Fig. 4.. Fig. 4 is a transverse section on the line 4. 4. of Fig. 3. Fig. 5 is a detail View of a device for raising and lower- `ing the movable rod by means of a rack and pinion.

A and B represent two rods of Wood or metal,

the rod A being placed in proximity to and In the face of the rod B is made aldovetail grove O, and on the opposite side of .the face of the rod A is a tenon D, adapted to enter said groove, lso that said rods are at all times held in juxtaposition. On the upper part of the rod A is a shoulder E, which may be provided with a metalcap F. Surrounding the inner portion of this shoulder'and the rodAis a metal strap G which carries on the front side of rod A'the upper target lH. The strap G is rigidly secured to the rod A by thev screws I. When the rod A is slid down Vupon the rod B, the upper end of rod B enters the strap Gr and has a bearing against the shoulder E of rod A. So, also, the lower end of rod A bears against the shoulder J on the lower portion of the rod B, and on the extremity of rod B there is also provided a metal cap or guard K. When the two rods are thus closed together, the ends of one bearing on the shoulder of the other, they may measure aboutl six feet in length and about one by one and a half inches in cross-sectional dimension.

Secured to the rod B by the screws L is a strap M, which 'carries the lower target N.Y Also secured to the rod B by the screws O is a strap P, through which passes the set-screw Q, by means of which the two rods are clamped together after the rod A is slid up or down as much as maybe desired. On the rear side rco of the rod B there is secured in a suitable bracket R a spirit-level S, and below the spirit-level S is also secured to the rod B a handle T. On the side of rod A maybe formedl or secured a toothed rack U. With this rack engages the pinion V, which is supported in a bearing W, attached to rod B. Said pin-1- ion is turned by the hand of the operator by means of the milled head X.

The front side of rod A is graduated to hundredths of feet, commencing by about two inches from the top at the zeromark, Fig. 2, and each graduation is preferably in multiples of two, as shown.

The upper target H, which is permanently' secured to the rod A, has a slot a', through which graduations on the front of the rod can beseeu, and its horizontal lines l) and ccoineide with the zero-mark of the graduations. The lower target N also has a slot d, through which the graduations on the front oftherod A can be seen. This target is to besecured immovably, as stated, upon the rod Bata distance from the lower end thereof corresponding to the height above the ground of the transit instrument used.

The inode of operation ofthis'rod isasfol` lows: The rodman faces the transit instrument, holding the apparatus vertically. With one hand he grasps the'rod B orhandle 'l thereof, if it be present, so as to hold that rod vertically and immovably. With the other hand he raises or lowers'the rod .A by` turning the milled head X, or if no lowering device ysuch as shown in Eig. 5is present he simply grasps the rod A with his hand. In, this way the rod A is moved in a vertical di-iv rection until the horizontal lines b c of .target Il and ef of target N are'brought into coincidence with the proper wires of thesight.'` The rods A and B are then clamped by means of the clamp Q, and the horizontal lines ef, of the lowentarget then point to the gradua-' tions marked on the front of the rod A,-which is the correct rod-readin g required. `Frac-1 tional parts of the graduation may be read by` the Vernier g, which is disposedon one side` of the slot CZ on the lower target. x

From the foregoing description it will be; seen that neither of the targets is movable upon the rod which supports it and that to move one target with reference to the other all that is required is a simple movement in` one'direction, after which the rod can be di-` rectly read in figures. Furthermore, as the lower target N is immovably fixed at the height of instrument-mark it is always in correct position.

The graduation-scale on the front of rod A is preferably made of a metal plate secured on said rod instead of on the wood of the rod itself. Especial attention is called to the fact that not only grad nations, but numbers in proximity thereto, are employed, so that the reading of the rod may be instantly obtained.

I do not limit myself to the use of a racky and pinion, as shown in Fig. 5, for raising and lowering the rod A, inasmuch as any other suitable device for that purpose may be substituted, or it may be omitted altogether, the operator merely moving the rod by hand.

I claim- 1. In a stadia-rod having two adjustable portions, one of said portions having a graduated outer face, two targets both facing in the same direction ldisposed in front of said face and supported respectively by said rods, substantially as described.

2. In astadia-rod, a fixed portion and a movable portion adapted to slide on said fixed portion, the said movable portion being provided with a graduated scale on its outer face, a target secured on said movable portion, and atarget secured on said fixed portion, said last-named target being disposed in front of said graduated scale, and provided with au opening exposing said scale, substantially as described.

3. The combination in a stadia-rod of two rods constructed to slide one upon the other longitudiuallggone of said rods being provided with graduations on its outer face, meansforholding said rods in juxtaposition, a 'target-supported on said graduated face, a second target disposed on said graduated face andhaving 'an opening exposing said face,

and'means for supporting said second target on said non-graduated rod, substantially as described 4c. IThe combination in a stadia-rod of the rods A, B constructed to slide one'upon the vother longitudinally, said rod A being provided with graduations and numerals ou its oute1i`ace,'means for holding said rod in juxtaposition, a target II supported upon the graduated face of rod A and a target N sup- 1 lthe outer surface of rod A, target Hsupported on said rod A, strap M on rod B and target N carried by said strap; said target N being `disposed in front of said scale and having an opening through which said scale is exposed.

V6. The combination in a stadia-rod of the rods A, B, said rod A having a graduated scale on its outer face, means for holding said rods in juxtaposition, means for causing rod A to slide on rod B, a target H supported on rod A and a target N supported on rod B; said target N being disposed in front of said scale and provided with an opening through which said scale is exposed, substantially as described.

GEORGE L. SANDERSON.

Vtitnesses:

FRANCIS T. WILSON, WM. R. PEoPLEs.

IIO 

